## What this PR does
To use the new VPC feature, users need to pass the subnet ID to the VMs
they wish to launch in a given VPC/subnet. As the dashboard cannot
compute the subnet ID in the same manner as the Helm template, a helper
configmap is created, containing the details of the subnets attached to
a given VPC. This configmap is queried by the dashboard frontend to
render those details to the user.
### Release note
```release-note
[vpc,dashboard] Expose subnet details to end-user in the dashboard.
```
Signed-off-by: Timofei Larkin <lllamnyp@gmail.com>
